JP3264024B2 - Toner for developing electrostatic images - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image developing toner used in an electrophotographic system or the like.

[0002]

2. Description of the Related Art Electrophotography is disclosed in U.S. Pat. No. 2,297,691.
No., JP-B-42-23910 and JP-B-43-2
As disclosed in, for example, Japanese Patent No. 4748, an electrostatic latent image is generally formed on a photoreceptor containing a photoconductive material by various means, and the latent image is charged in advance. And then, if necessary, transfer the powder image to paper or the like, and then fix it by heating, pressing, or solvent vapor.

At this time, as a developer for developing an electrostatic latent image formed on the photoreceptor, the toner itself is carried to the vicinity of the photoreceptor by magnetic force while carrying the toner on the surface with the toner by electrostatic force. Particle size 30 to 200 called carrier
A two-component developer composed of iron powder, ferrite, magnetite or the like having a size of about μm and a one-component developer composed of only toner without requiring a carrier are known.

The toner is a powder obtained by dispersing a colorant (dye, pigment), a charge control agent and the like in a binder resin such as styrene acryl and finely pulverized to about 1 to 30 μm. Nigrosine dyes, triaminophenylmethane compounds, 4
Charge control agents such as quaternary ammonium salts have been known.

[0005]

However, these conventional charge control agents are not always sufficient in the effect of imparting chargeability, and in particular, in long-term repeated copying, fog (image stain on a white background), reduction in image density, etc. And the image quality is degraded.

In order to solve these problems, it is of course to provide an appropriate charge amount at the initial stage, but to develop a toner having a small charge change and excellent charge characteristics in long-term repeated copying. is important. SUMMARY OF THE INVENTION It is an object of the present invention to provide a toner for developing an electrostatic image having high image quality in long-term repeated copying and having excellent charging characteristics.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that acidic carbon black which has conventionally been avoided because it has a tendency to be negatively charged and a compound having a specific structure It has been found that, by incorporating the toner into the toner, a long-life toner having high image quality and excellent charging characteristics can be obtained in long-term repeated copying.

Hereinafter, the present invention will be described in detail. The compound having a specific structure according to the present invention is represented by the following general formula [1]. General formula [1]

[0009]

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(Wherein R ¹ , R ² , R ³ and R ⁴ each represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aralkyl group, and A represents an aromatic group which may have a substituent. Represents a ring residue, and n represents an integer of 2 or more.) Specific examples of the substituents R ¹ , R ² , R ³ , and R ^{4 in} the general formula [1] include a methyl group, an ethyl group, and a propyl group. ,
Isopropyl group, n-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonanyl group, decyl group,
Alkyl groups such as undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group and stearyl group; aralkyl groups such as benzyl group; lower alkyl-substituted benzyl group, nitro-substituted benzyl group, and halogen-substituted benzyl group And the like. Of these, dodecyl, tridodecyl, tetradecyl, hexadecyl, stearyl, benzyl and substituted benzyl groups are preferred. It is also preferred that R ¹ and R ² are methyl groups, and that the total number of carbon atoms of R ³ and R ⁴ is 13 or more, preferably 19 or more, more preferably 30 or more. .

A in the general formula [1] represents an aromatic ring residue which may have a substituent, particularly preferably a benzene ring or a naphthalene ring, wherein the substituent is a hydroxyl group, an amino group or an alkyl group. And a hydroxyl group is particularly preferable.
You may have two or more substituents. n represents an integer of 2 or more, and preferably 2 or 3.

Of the general formula [1], those represented by the following general formula are particularly preferable.

[0013]

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(Wherein R ³ and R ⁴ represent an alkyl group;
The total number of carbon atoms of R ³ and R ⁴ is 19 to 50, and the naphthalene ring may have a hydroxyl group as a substituent. Among them, those represented by the following general formulas [3], [4] or [5] are particularly preferable.

[0015]

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[0016]

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[0017]

Embedded image Specific examples of the compound represented by the general formula [1], which is suitable for being contained in the toner for developing an electrostatic image of the present invention, include compounds represented by the following structural formulas. It is not limited to these. Exemplified compound A

[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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(18) In the general formula [I], R ¹ = CH
₃ , R ² = CH ₃ , R ³ = C ₈ H ₁₇ , R ⁴ = benzyl group, A = 1,5-naphthalenedisulfonic acid ion (19) In the general formula [I], R ¹ = CH ₃ , R ² = C
H ₃ , R ³ = benzyl group, R ⁴ = benzyl group, A = 1,
5-naphthalenedisulfonic acid ion exemplified compound B

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

The compound represented by the general formula [1] can be used in the present invention irrespective of the production method, and an example of the specific production method will be described below. The compound represented by the general formula [1] is generally, for example, a compound represented by the following general formula [II]

[0043]

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A quaternary ammonium halide compound represented by the following formula is reacted with a compound represented by the following formula [III] or [IV] by heating to about 70 ° C. in water or alcohol. It can be obtained by:

[0045]

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(Wherein, A has the same meaning as in the general formula [1], and Y represents an alkali metal such as sodium or potassium.) The content of the compound represented by the general formula [1] in the toner is bound. The amount is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the resin.

If the content of the compound represented by the general formula [1] is too small, the effect of imparting chargeability cannot be obtained, and if it is too large, improvement in charging characteristics cannot be expected. Acidic carbon black is used as the colorant contained in the toner according to the present invention. Acidic carbon black refers to those having a value of 6 or less when the pH of a suspension obtained by boiling carbon black and pure water is measured, and acidic carbon black having a pH of 2 to 5 is particularly preferred in the present invention. used. The amount of the colorant is preferably 3 to 20 parts by weight based on 100 parts by weight of the resin.

Heretofore, acidic carbon black tends to be more negatively charged than neutral or alkaline carbon black, and therefore tends to be avoided in positively chargeable toners. Carbon black not only plays a role as a coloring agent, but also plays a role as a resistance adjusting agent as an electric conductor, and also affects the chargeability of the toner. For coloring power and charging stability, it is important that the toner is uniformly dispersed in the toner. Styrene acrylic resin, polyester resin, epoxy resin, etc., which are generally used as a binder resin for toner, are inherently negatively charged, so that acidic carbon black is easier to disperse uniformly and should be advantageous. Positively charged toners tend to have too low a charging characteristic. On the other hand, since the compound represented by the general formula [1] is excellent in positive charge imparting property, the negative effect of the acidic carbon black can be offset, and the synergistic effect of the acidic carbon black and the general formula [1] can be offset. Thus, it is presumed that a positively charged electrostatic image developer having excellent charging characteristics can be obtained.

Specific examples of commercially available acidic carbon blacks include MA7, MA8, MA11, manufactured by Mitsubishi Kasei Corporation.
MA100, # 1000, # 2200B, # 2350,
# 2400B, MOGUL L, RE manufactured by Cabot
GAL 400R, MONARCH 1000, etc. 1035, 104 of Raven series manufactured by Columbia
0, 1255, 3500, etc., and the specific surface area by the BET method is preferably from 25 to 400 m ² / g, and the oil absorption of dibutyl phthalate (DBP) is preferably from 40 to 140 ml / 100 g, and particularly preferably from 80 to 150 m ² / g. , Dibutyl phthalate (DBP) oil absorption of 50 to 120 ml / 100
Those in the range of g are more preferred. It is also preferable to add a small amount of acidic carbon black treated with a metal salt of a carboxylic acid having a melting point of 70 to 250 ° C., if necessary.

The binder resin contained in the toner according to the present invention can be selected from a wide range including known ones, for example, polystyrene, crotopoistyrene, poly-α-.
Methylstyrene, styrene-chlorostyrene copolymer,
Styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-
Vinyl acetate copolymer, styrene-maleic acid copolymer,
Styrene-acrylate copolymers (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, and styrene-phenyl acrylate Copolymers), styrene-methacrylate copolymers (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, and styrene-phenyl methacrylate copolymer) ), Styrene-based resins such as styrene-α-chloromethyl acrylate copolymer and styrene-acrylonitrile-acrylate copolymer (a homopolymer or copolymer containing styrene or a styrene substituent), a vinyl chloride resin, Rosin-modified maleic resin,
Phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin and polyvinyl butyral resin,
Particularly preferred resin for use in the present invention is styrene-
Acrylic ester copolymers, styrene-methacrylic ester copolymer resins, saturated or unsaturated polyester resins, epoxy resins and the like can be mentioned.

The above resins are not limited to being used alone, but may be used in combination of two or more kinds. The toner according to the present invention can be added from a wide range including a known one such as a release agent, if necessary. Known release agents can be used. For example, low molecular weight polypropylene resin and polyethylene resin are used. The amount used is preferably from 0.1 to 10 parts by weight, more preferably from 1 to 5 parts by weight, per 100 parts by weight of the resin.

In addition, TiO ₂ , Al
By adding an inorganic fine powder such as ₂ O ₃ or SiO ₂ and coating the surface of the toner particles with these powders, the fluidity and aggregation resistance of the toner can be improved. The addition amount is 0.
About 01 to 3.0% by weight is good. The toner of the present invention can be used as a so-called one-component developer such as an encapsulated toner, a polymerized toner, and a magnetite-containing toner, in addition to a two-component developer.

The toner production method of the present invention can employ various conventional toner production methods. For example, the following example is a general production method. First, resin,
The colorant and the like are uniformly dispersed by a ball mill, a V-type mixer, an S-type mixer, a Henschel mixer, or the like. Next, the dispersion is melt-kneaded with a double-arm kneader, a pressure kneader, an extruder, a roll mill, or the like. The kneaded material is pulverized by a pulverizer such as a hammer mill, a cutter mill, a jet mill, and a ball mill, and the obtained powder is classified by an air classifier or the like to obtain a toner having a desired particle size distribution.

As a carrier which is mixed with the toner of the present invention to form a developer, known carriers such as ferrite, magnetite and iron powder having a particle diameter of 20 to 500 μm, more preferably about 30 to 200 μm can be used. Further, those whose surfaces are coated with a silicone resin, an acrylic resin, a fluorine resin, a saran resin, or the like, or a mixture of these resins can also be suitably used.

In order to prepare a developer by mixing the toner of the present invention and a carrier, the developer varies depending on the particle size and shape of the carrier and the particle size of the toner. It is better to carry out in a range of about 9: 1. Various mixers and shakers such as a V blender, a ball mill type mixer and a reciprocating shaker can be used for mixing.

[0056]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention. In addition, in each of the examples and comparative examples, “parts” simply means “parts by weight”.

[Production Example of Exemplified Compound A (12)] 2 liters of demineralized water was placed in a 3 liter four-necked flask, and distearyl dimethyl ammonium chloride 1 was added.
00 g (0.17 mol), the water temperature was raised to 80 ° C.
The mixture was stirred at a time of 220 to 250 rpm for dissolution.
A solution prepared by dissolving 34 g (0.10 mol) of sodium 1,5-naphthalenedisulfonic acid in advance at 200 ° C. with 200 ml of demineralized water was mixed with the aqueous solution of chloride over 30 minutes.

After the mixture was stirred at 80 ° C. for 2 hours to carry out a reaction, the mixture was allowed to cool while continuing to stir for 2 hours.
Left overnight. 1 L of demineralized water was added to the granular crystals obtained by filtering the liquid, and the mixture was washed by stirring at 170 rpm for 30 minutes. After the filtration, the same washing operation was performed, followed by filtration again. , Dried for 12 hours and the desired bis (distearyldimethylammonium)
As a result, 115.9 g (yield: 97.9%) were obtained as light yellowish crystals of crude crystals of 1,5-naphthalenedisulfonate. The powder X-ray diffraction pattern was as shown in FIG.

For recrystallization, 100 g of the crude crystal was placed in a 3 liter four-necked flask together with 1 liter of methanol.
After refluxing for 0 minutes, the mixture was cooled on ice and stirred at a liquid temperature of about 2 ° C. for 30 minutes. The precipitated crystals were filtered and dried by a vacuum drier.
After drying at 6 ° C. for 6 hours, 78 g of purified crystals (total yield 76.4).
%) And a melting point of 272 ° C (decomposition). FIG. 2 shows a powder X-ray diffraction diagram of the obtained bis (distearyldimethylammonium) 1,5-naphthalenedisulfonate, and FIG. 3 shows a solid-state C ¹³ -NMR measured under the following conditions.

[0060]

[Table 7] Apparatus used: NMR Bruker MSL-3
00 Measurement conditions: ¹³ C-CP / MAS method Waiting time 5 s Integration frequency 350 times Contact time 1 ms Rotation speed 5.5 kHz

Embodiment 1

[Table 8] ・ Styrene-n-butyl acrylate copolymer resin 100 parts (monomer ratio = 82/18) ・ Acid carbon black 5 parts (MA8 pH = 3.0, manufactured by Mitsubishi Chemical Corporation) ・ Exemplary compound A (1) 1 part ・ Polypropylene wax 2 parts (550P manufactured by Sanyo Chemical Co., Ltd.)

The above-mentioned materials were mixed in a hot roll mill for 150 hours.
The mixture was melted and kneaded at a temperature of 0 ° C., cooled, coarsely pulverized using a hammer mill, and then finely pulverized by an air jet type pulverizer. The resulting fine powder was classified to select a particle size of 5 to 20 μm to obtain a toner having an average particle size of 10 μm. For the toner particles, silica fine powder (R972 Nippon Aerosil)
Was externally added by 0.3% by weight with a Henschel mixer to obtain a black toner.

This toner and a carrier obtained by coating a methyl silicone resin on ferrite powder having an average particle diameter of 100 μm and a carrier of 96 parts with respect to 4 parts of the toner were mixed using a V blender to obtain a developer (positive chargeability). . This developer was subjected to a continuous actual copying test of 100,000 sheets using a commercially available dry photocopier using an organic photoconductor as a photoconductor. As a result, the charge amount was stable, the fog was small, the black portion of the copy was high in density and uniformity, and a high-quality copy excellent in gradation was obtained.

Example 2 MA-100 (pH = 3.5) as acidic carbon black
A toner and a developer were prepared in exactly the same manner as in Example 1 except that Mitsubishi Kasei Co., Ltd. was used. This developer was subjected to a continuous actual copying test of 100,000 sheets using a commercially available dry photocopier using an organic photoconductor as a photoconductor. As a result, the charge amount was stable, the fog was small, the black portion of the copy was high in density and uniformity, and a high quality image copy excellent in gradation was obtained.

Example 3 RAVEN 1255 (pH =
2.5, manufactured by Columbia Co., Ltd.) and Exemplified Compound A (12), except that a toner and a developer were prepared in the same manner as in Example 1. This developer was subjected to a continuous actual copying test of 100,000 sheets using a commercially available dry photocopier using an organic photoconductor as a photoconductor. As a result, the charge amount was stable, the fog was small, the black portion of the copy was high in density and uniformity, and a high quality image copy excellent in gradation was obtained.

Comparative Example 1 A toner and a developer were prepared in exactly the same manner as in Example 1 except that # 44 (pH = 8.0, manufactured by Mitsubishi Kasei Co., Ltd.) was used as carbon black. Using a dry copying machine using a commercially available organic photoconductor as a photoreceptor,
A continuous photographing test of 000 sheets was performed. As a result, the charge amount changed to a higher level, and there was no problem of fogging. However, the density of the black portion of the copy changed to a lower level, and characters were blurred and high quality image quality could not be obtained.

Comparative Example 2 A toner and a developer were prepared in the same manner as in Example 3 except that # 45 (pH = 8.0, manufactured by Mitsubishi Kasei Corporation) was used as carbon black. Using a dry copying machine using a commercially available organic photoconductor as a photoreceptor,
A continuous photographing test of 000 sheets was performed. As a result, although the initial image quality was not a problem, the charge amount increased as the copy was repeated, the density of the black portion of the copy was low, and only a copy of low quality with no uniformity was obtained.

[0068]

The toner of the present invention is a toner having excellent charging characteristics, which can be maintained without deteriorating the initial high-quality image quality in long-term repeated copying.

[Brief description of the drawings]

FIG. 1 is a powder X-ray diffraction diagram of a crude crystal of an exemplary compound (12).

FIG. 2 is a powder X-ray diffraction diagram of a purified crystal of Exemplified Compound (12).

FIG. 3 shows a solid C ¹³ − of a purified crystal of the exemplary compound (12).
NMR diagram.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hitoshi Ono 1000 Kamoshita-cho, Midori-ku, Yokohama-shi, Kanagawa Pref. Mitsubishi Chemical Corporation Research Institute (56) References JP-A-4-57064 (JP, A) Hei 4-70849 (JP, A) JP-A-6-59518 (JP, A) U.S. Pat. No. 4,990,426 (US, A) U.S. Pat. No. 5,054,423 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB (Name) G03G 9/08

Claims (1)

(57) [Claims] 1. An electrostatic image developing toner comprising at least a resin, acidic carbon black and a compound represented by the following general formula [1]. General formula [1] (Wherein, R ¹ , R ² , R ³ , and R ⁴ each represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aralkyl group, and A represents an aromatic ring residue which may have a substituent. Represents. )